Golfer changes agent. So what? It should be right up there with "man changes bank", or "rock star changes dealer".

Except the golfer is Rory McIlroy, thus it is perceived to mean an awful lot. In Shanghai yesterday, the Holywood youngster explained how this realisation has hit him since he split with Chubby Chandler's ISM two weeks ago.

However perverse, however absurd, this was a confessional box he just had to enter. Granted, he did not spill his soul. And many did depart the huddle at the Shenshan International GC with something greater than a mere submission that it had been "only a business decision, nothing personal" which caused a 22-year-old, after the best year of his career, to leave the management company which had guided him since turning pro.

But he faced up and answered the questions. At the same time as looking utterly mystified by all the fuss.

"I was surprised at how much of a big deal was made out of it, because these things happen out here all the time," said the US Open champion, after his final practice round for the WGC HSBC Champions. "It just seems that with me it's made a bigger deal. It's not that big a decision."

Of course, it was "big" in terms of what it meant to Chandler -- if McIlroy has the type of success most people predict, it will probably cost ISM tens of millions of euro.

"It was probably the hardest decision I've ever had to make," said McIlroy. "And it's the toughest conversation to sit down with the person who has been there for you for the past 10 years. Look, I'll never forget what Chubby and ISM have done for me. They're a huge part of my career and if it wasn't for their help, I wouldn't be in this position."

It was the timing that caused the biggest ripples. McIlroy has won his first Major, and with the stock of Tiger Woods still in free-fall, the noughts on his portfolio were lining up.

And when he informed Chandler in an airport lounge in Bermuda, he had just spent two weeks in his company on a seven-day, seven-city exhibition in China and then four days at the Grand Slam of Golf. Chandler, a larger-than-life figure who prides himself on having his finger on the pulse, understandably felt like he had been left at the altar.

However, McIlroy maintained this was not a fit of pique.

"It's not a decision I made overnight," he said. "I thought long and hard about it and I spoke to my mum and dad, who are 100pc behind any decision that I make. It really wasn't personal; it was just business."

In the aftermath, Chandler indicated that he, too, thought the reason was primarily business -- essentially that McIlroy wasn't pleased with his "brand", nor with the stature of some of his sponsors. There was even speculation that his burgeoning relationship with world tennis No 1 Caroline Wozniacki had turned his head.

McIlroy dismissed all that with something resembling a harrumph.

"I felt like, for four years, Chubby was the best person and ISM were fantastic for me," he said. "But sometimes, to progress, you need to have a fresh view on things. And this was something I felt I needed.

"It's not about endorsements or anything like that. It's about me trying to play my best golf. And that's all there is to it. And I feel that a new environment around me would enable me to do that. I can't put a date on when I decided. I'm not saying that it has been in my mind for a few years, but I have always seen at close hand how great a job Conor (Ridge) and Horizon have done for G-Mac (Graeme McDowell)."

McIlroy is not denying he has changed. But he fails to see why the cynics believe that all the success has altered him for the worse.

"Of course I've changed," he said. "It's all part of growing up. I'm still only 22 -- there are people my age who are still at university. I've had a lot of life experiences over the past few years. I feel like the (Unicef) trip to Haiti changed me; I feel like winning the US Open changed me.

"So there have been a lot of things this year that have maybe not only changed me as a person, but also changed my view on things."

The young Tiger comparison is inevitable. He, too, switched managers as the spotlight intensified and he, too, was forced to accept that every minute detail of his life would be placed under the microscope.

"Yeah, I've been shocked at my profile," he said. "The things that go on... well, to my mind, it doesn't seem like a big deal. I don't know whether it's just me.

"I've said a few things this year that I probably should not have -- for instance, after the Open when talking about the bad weather and how I wasn't going to change my game.

"Some things you say in the heat of the moment that, if you actually thought about a bit, you wouldn't say.

"Apart from that, I just try to be honest. I always want to be that way, I don't want to be guarded and give meaningless answers. I still want to be myself."

Himself now is quite something to behold. Last night at a HSBC function, he joined Wozniacki on a simulated tennis court which measured their speed of serve.

This is the only time in McIlroy's life where he will be laughed at for shooting 59 against someone who scored more than 100. The mph clock made for hilarious viewing. Yet this morning he resumed his day job, not as one half of sport's famous couple, not even as the heir to the Tiger circus. But as the boy from Holywood who has his eyes on another title.

Last week, he won €1.4m at the Shanghai Masters and now he attempts to win just his fifth title at this World Golf Championship extravaganza. The €840,000 first prize would leave him €450,000 short of world No 1 Luke Donald in the European Tour Order of Merit.

"I'm a long way behind Luke, but I have a chance here to cut into his lead," he said. "That's all I'm concentrating on." If only it was so simple.

Meanwhile, McDowell thanked heaven for the opportunity to tee it up at the HSBC Champions today and forget the worst weekend of his career.

"The great thing in golf is that you start at level par the following Thursday," said the Portrush man, who closed with crushing back-to-back rounds in the 80s at Valderrama, the toughest venue in Europe.

"I picked the wrong course to get 'the lefts' and hole nothing," he explained. "I took a few risks when out of position and got into worse trouble.

"My swing is elusive for me at the minute. My good swings are great but the bad ones are out of control."